We can have multiple threads in a single process.Thus we 
can say threads are working units of a process.

1)
process is self loadable
while
thread is depends on operating system

2)
communication is possible between processes through some 
mechanism
ex:shared memory, message queues
communication is possible between threads directly

A thread is building block of process, there can be 
multiple thread or at least one thread per process.
Process is self loadable but thread need a process to run.

Thread uses shared memory. But process uses different 
memory.

We can execute a process (EXE) but threads can be created 
and executed from inside a process

Thread is a path for execution and the executable which is 
running is called a process.